Investigation On The Size Distribution And Microstructure Of Sprayed Powder Of GCr15 By Spray Forming

Sprayed powder is a kind of by-product which formed in the process of spray forming inevitably. The metal droplet atomized by liquid metal, the powder formed when the metal droplet flying and missing the basis solidification of deposition. The research on sprayed powder is helpful to the understanding of atomizing process. The solidification of spray deposition and the formation mechanism of its microstructure can be analyzed deeply from the study of morphology and solidification structure of sprayed powder.The sprayed powder of GCrl5 is produced by spray forming equipment. The size distribution, microstructure and composition of the sprayed powders are studied through Scanning electron microscopy (SEM), optical microscopy (OM) and so on. The solidification mechanism of atomization droplet during this process has been investigated.The result show that the size of sprayed powders of GCr15 is ranging from 0μm toΦ130μm, among them the powders ranging from 0 toΦ60μm take more than 90% and powders ranging from 30μm~60μm take 51%. The average radius of particles is 60μm. 10% of the sprayed powders adhere together and part of small particles enters into the big ones.The SEM and OM show that some powders adhere together and part of small particles enter into the big ones. Both of these have similar microstructure. Small particles is the center, radius directional microstructure distribution is followed by chilled spherical crystal region, cellular crystal region and dendritic crystal region. The main reason of this organization is the Latent heat release from chilled layer of 0μm~5μm. As a result of the fast cooling of particles, the time of element segregation is not enough and different microstructure are relatively homogeneous in composition.